SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41f66312cb36a55c621742c5c30894ee17494477bd88cd3c2818c902e23a587e' 
  AND token = 'JVIYMqu0S36xboWSiGfW4OfPx8WAle7hSEdLU07UWEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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