SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68350c22c0f9797ab571d635c4874ce3d25631beccb02f3091740b461a248bfe' 
  AND token = '96weI6ZeUYfj2Sh1Y0yQGhBG1PvUveZocWUbw1i046Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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