SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '825290e09484be8def16475448fea55d696282572da8473112e6d4eff915a670' 
  AND token = 'FtowQhF81NIh23rov7FKtVBtEYVG0A8CwO9lQHFLIwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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