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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19640b7226fe467ecf0e0641dce477cdbe4dc286c97d76247aebef61f63f6d45' 
  AND token = '0XLWlom1dUths0ZR0IEkecyBEI30Rka+tN4k40k/xAg=' 
  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"
    }
  }
}