SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8f0393fb3392ceb076f66a82d4d52fb3e9c1a75ef3d78d99a6238759de419bb' 
  AND token = 'Y/8U2yvDWobcwrsjgF0JYAaOmmCGKuQBV05Tsm/4n7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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