SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3bb937aa9eb30b4a02675b0317af04f53609be8e8ca4766790abc25ed1a01f6' 
  AND token = 'hj6RWkibrVtiEI3b52im/XW+klLz3MHJEXWWAG0bn5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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