SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78adfea5d306a7bf5473c927cbdeaa8aab1154ff7623f6d9f152d57a46cf50a4' 
  AND token = 'llYSxybkmIZe1EXtmZ0LuqBo/1PxnNpbYp5k2OdTNVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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