SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '920e17147f0fe30e30f905bf35ac94f5a641a8a836820cfd2bd4b517a9718d10' 
  AND token = '2GaiSlZd2DErxDzn3A0e6qQC8cLnbrVunN4sHHSMoIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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