SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2d7422ebdf2bd2148da144208d38eb8977a289883e2886f00db4a8643ede47a' 
  AND token = 'bZLJWwm0Qf0Vusq/WPmH/zDqdUi7+D8kjjDFr0lkbng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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