SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44654ce5bceabf254f995d735b582b02f5853389e956cb1fc7b78be764f6a68f' 
  AND token = 'CyNOw8FzqLbTAZiFtFDK+/jxd1SZC3OA7hiYofvfKp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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