SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '041e2b51301f7feb3d0dffe82c43c78e0c333988530b03b34ffe51f8c1037c38' 
  AND token = 'jU6kjdH3sP6VCEpsZFl92vnUPxgZmye5otLPPsVT5vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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