SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6385269228e5e1f047aed300c346846d02f80f617aeb3243f39ad3424ffab512' 
  AND token = 'zgYHTh0cjfkdN+IJd/xxTFzm+LuvDjFtBQF0JyE4lQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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