SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f10456c709e13efd92c3cfec5a3e720f6f6c9d2745ae4493cd8d6aca274b79c0' 
  AND token = 'pSMLbF3ljEkgS56CKMSQIj7GQGA7lYIGo5JHDSqt0+w=' 
  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"
    }
  }
}