SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c66e4c49be36674d7cab8beff4e13101b8589bd35ced914866365a516fa7945' 
  AND token = 'qZ+Shuofu8jXqac/NjACXMlTyKoVPlPxvnXhfTh5jyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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