SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '413051233629b7aafe77049fa9181725adf6af6109c6b3e23c6ea41967404799' 
  AND token = 'ojt7S27KfTHY6zJcKSJs10nPeyIJ7sQiBEiBcGfevVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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