SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d11d23e79e186e582ebf3c2506fe50d953ac5ee94d10847df2674c456cca36a' 
  AND token = 'kxQffbzto9nrTEr6gKlSExLuEq1IqJvKgjPWrkWyhjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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