SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ccd0a0aea7c220a8eff8adefe0342d65a84d640688ed98eababd7e3219b997' 
  AND token = '1ymFXUYESNVmYhtoJrXl6lm38gPuyvpKziJxT/epiFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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