SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9910322480f23f05a442633026ddb1e4773a93d5bb248ffc661f9a340c6c392' 
  AND token = 'gsxJ/K4YOrLqFDwr1FM1D8u6L48yg9D0yMe+F/XQhVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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