SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16aac7fbda0c52c133e1960d9ec91dfd0647de4ba531da53c0e78c21b2970f2' 
  AND token = 'XyYOO6IB5N36ToH/+x6wuRdUXWaezikZ9WPvE0QJypw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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