SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '272378545963724f679b26940cb15e3a80f2a31d84c597866c420ffe44b63bcd' 
  AND token = 'kBe0J4H1SuYjg9+/sgdORm7FD4JQQ7XjvW26FKt6mlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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