SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49be560b3fcd8273922d54c321a8baa74a25945f07db3d1ad255e97e90540bd1' 
  AND token = '/Le996PQPKJ11X9u8nPXZmmNI1EhSmdlK/msJwFqTfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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