SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f9c956fd75fc7ef3911ba9565cbea10155b8d07ced837630a59bcbffc69970a' 
  AND token = 'cELknMfgA/PDvdDUtiWbDRFSb/b3ZiX8tVSsIk8ploA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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