SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '35c92c880926e48530652dc481bde8b2fa02e0d8945fba0a1268ed4154a404ef' 
  AND token = 'gzrfzQjOg1Cyt6BHoeUSi8gZIft8UlhX0Z7AqA0NVOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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