SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3376bc55bebfbe11f79c7b5c8faf132f50430f795701c3c5de7e0f625f352051' 
  AND token = 'LaL9sgLYHeG9+ABBVWZFzesXELbS2jT8+ijCh/xqHdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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