SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b353c73734889a8a8a25de1e3c1586928d359045c7ac2baf34ee6fbd9848ecd' 
  AND token = 'dPOFMQlGCJvpbejKHRxhFi82HIRAhpByCh//FmCeyUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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