SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a37cadbaf5cee95f1c3d00c04398994cafab2757cfb95d8588885782256246' 
  AND token = 'OedXlxHKojJUF/gS81bntw+841LR32yTnb9jyqZHxjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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