SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb3c258bdc81db2cdf6ddbc7fbfd6cea375de9b80b67b7d047e8012f5286290' 
  AND token = 'lsIKaYV9Pi2XwR6NpT393bUy4cuWvj7BGCFVLWmT3DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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