SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66af6484cc584588d928aec1577a53eeaa1af731136ba3d556ee543a4163e726' 
  AND token = 'RsHfXRfeH1HKw7UhClfcLJEOPvhMyDmZdgWl8H884as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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