SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe3acad473d78e7e497c6be6327a3b4edd651ed51d39cb3d5220b437cdc25d80' 
  AND token = 'xvCd9Q49b/xiERx/mQgq9yaUbXRr9ZBRnBq3y9+WsmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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