SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad6f6f630c61ef51caca58ceb8f297835bad8714ff5084395869b14362b5280c' 
  AND token = 'xDi3DgwGbZX/vb1L90sRdFXAXx4CLj1xwVogYhzIsjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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