SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c44efc2ccd8462d0b30e396f9971c1792274585194bdfc7578073b0033174348' 
  AND token = 'qZuT9FqOL5mTFiK8ZkUXzIC/75kcfTJhJz3wv6G6g1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}