SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4b0cec36e6347146a981fe9621e2999bc3adcc0eced99fd5bbd4c060c28f3f6' 
  AND token = '5Nofy6wxaRHNdzjfAINTVuYZa4lHgzP3Pg3vTqHe1Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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