SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31e964c241f13305afa345e4d73219749e15074777ec8d37aa5e9523128c725c' 
  AND token = 'v20udcESpF+ufvsox1r3BdXiHA5BZ6mrEx31pQ/ENfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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