SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e7133c76068404b850e3d0bda4c064832095c834ec5f3485e45cf781814e3dc' 
  AND token = '80zZJQTRrkRWrF2nOi+lHYrYzQWcMJ65CgAumSDyxZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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