SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8a58e38a4cab462dc63b1258b98d1feaeac3309b57c0015a8bf3045ec877ed1' 
  AND token = '6jXcTZuuvTuyUufM43vXLIBJxBbno2BO1cwrTdpSvkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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