SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a57c795f0a7b10fa48e7e543570d865bd1ce9e056ab41dab40203bbbab7538' 
  AND token = 'i3fm9Plwo2H3F3Xmu4Lno8odGBRzoFDvN1BpSdVoQTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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