SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d305c96821f599646984c63bd747a3c834b9d9e79a3167e92785b0fd27ffdcb' 
  AND token = 'jyQlHpkq+NDcOYZLXFRgdSF8mXqSYRRYur+Fjnf9aGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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