SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7bd8ca231abb81289dffba0fbfb07cfcc8f63a29168603db56a44085eea2fce' 
  AND token = 'FWsFY5zVQtCgElr90qwldZ+lLqHY/hX223BB0aFh934=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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