SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff8263dccee688ee0ee400c4166a293207a25fab8286b7d15892ab6e5f761081' 
  AND token = 'b0wwGOoZleNcsAJVSyjFpMydrkO72bdjLKfEzToK45Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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