SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780274d85615112a5a7354273cdb902ceed6f964bd0bb59b7681419286e3b12a' 
  AND token = 'RY8cNrwRgC17vVFjRvoEC6soBxWWoNiqa5pyu8tugtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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