SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98976b59f9cd81c1e8a9850bc7a092189258fa35f067b2acf39a7b9cdc2c2d7f' 
  AND token = 'YUykEAb0SP8/sluJCbqbsYz8BqcdlEMIZ5b3/ubKgUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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