SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeb6bc38fcb464978e4864dfc3027c569a35ddc0f975b881ace2361d7044c8c3' 
  AND token = 'mLzz3CZPahMM4tR9nsCOBrGNJMEIGzTAj+oocIRLtlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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