SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49bedbb35e1ce606dfaca39511d4b325b6a197d294564cbf51bb0c4f6b1f647c' 
  AND token = 'TGwiEO7KlZCksLA0XMJap0TeLzGcA+5x5jUX4Sdz0ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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