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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68e2d0e06dcc45af1c2d3cea9ff218e8b2bf25d9efac699fec97a9cee30c4e66' 
  AND token = 'Bmb2Yl73BGI3vuRMp8+KB42q3E1qzx3ih2aqV/89C0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}