SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bde4931bff23805f635069e98cabf3d355de4e5191b8beb8a19bcf30541cf71' 
  AND token = 'z4VLi8VUJYkl/Q8LPftjnkWBQGf2zD2vEoGkkFkSUOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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