SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '490bc958e084660f23368d368e40c1c1a6362ffc2dd2ec81ce1425345bb27be7' 
  AND token = 'z2gpgxBuX91/KoRlsDHSejX4TEhN1QijNZx+JMN3Ycg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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