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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6dd39ebca15802e5c69b6208b3e2250c5825dfdaac190a68ee0e3cb7e0b1b04' 
  AND token = 'wbT/g5ub4Fd1w5/GpMVlSGd2CMYuIUSJdmfTMRIY0PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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