SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e658ec520165bc35a433ff80bf68223cd2b30bc796a142e0656e2132e52f75e' 
  AND token = 'MSw79UCcJOGY1XjLgDO12/dMYUUr3LcRBR5MyFxubpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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