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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8a9b3ad13fcd459f829b3eae3b3c8c519e9b04e08567656503c7c7b594776d0' 
  AND token = 'u2AMpQlsIkjdO1+pEQ7wg8pSp1Rw+HDVEMJv/kxeEbA=' 
  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"
    }
  }
}