SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08cf018c067ea1c3b6ff6ff81874eeb6ffdea946b9ec8bacea21e48c542e7ad0' 
  AND token = '6p/UNjsC4/ZcY4cxQvarDzSGX7xXPsoc5VYilbfUNec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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