SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6560b51c960a0523723693f4d2ef447f815811f4a93021ed7cf7570ff86549f7' 
  AND token = 'Hkz90v8td1++0c/lQm+ksHFMXphGeVr3kaB55O77B2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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