SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938df00c2f170ba1b3fbada8e64bf94047dc4682f034f20a9a3e6af074d5a064' 
  AND token = 'PJ4IUbdMIg8iX/BAq9PTsKLKRBtXnLdcKLjyi788TDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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