SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbd735caed8c349f175265cdf50a1d731a874ffbf25ec368af1fd2728a87fcb4' 
  AND token = 'RuijifKDjblZ+EhC2Zq/5l8UYnoOq/Kj2TgmnXoJ+ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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