SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59acee96284daf603c74ef02023ade87be8b3754bb4d54233b59aad0d71c63d1' 
  AND token = 'katKdFAQ8YoRiqsyUFXzzdmYlRSxlFNmxS0b4rckGdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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