SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb5fe6fd7159cd98c1258590ccc88ed6e3bdced1d29ce466dcc6e2448cb2ece7' 
  AND token = 'Y9guG/clgCctv1HSzJTw4vmpokHQBnc2ei5W5i8/fHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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