SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09d2a621549facd97ca7482d6881cbbf121e986ccb3a6642880a96234d5888da' 
  AND token = 'KreBmTuvV4ew0NcQoJ4ETwqrHoC6ASwCWN+02LiwGxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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