SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3977cdf703e45a23e38f71bf8c835d03b02891f1995f2d6f6caf8b58116a5c4' 
  AND token = 'bUvV3RnOtCxWexGvyYw1KuIHwv8+LHTGR2KEZRcFYVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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