SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b26936c3f7afd712bcd9c2e07a2b55f88309af2661ed13826a2a9cb8ed67edd' 
  AND token = 'y25XZZ2ZJdf8jiel1JsI2mxwOLG0f9EFBGfr4mcGzaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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