SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71195c0023adca9563d04918923b8440303de695372757f76e28e7ea37c1bdff' 
  AND token = 'aIDXyTx53Y4vZR0BT8gjLeqCXp8xlyu8dXlCEMvTsIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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