SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5889b38ad1a42e2eda4fafdc285d7464c4be54ff2c25651a76c5de7c4d9c4f8d' 
  AND token = 'uCjP3g2xCutS+sXqwj6KTzDRQhhVD0z+epbUHSd8Lz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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