SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2e71c8b22bed43b4daa57f1583ce841c07b4e5772416adb809c7bf02df36dce6' 
  AND token = '6h+KRfquMW7ywu+HXwRPRQoy2YXUGVDC192lo7iFU2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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