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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c68fb4d2b0aec12ba980602eb4c2c44592a9d616c0bc55f2ec5b0a85dfc06b5' 
  AND token = '5FVMA2s3sUbYdjLWO7DhQ5QHlA9Ucnuga4/PmWniqao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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