SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19ecb732e4291aeb4aafa2a32c99695f88cbb868b940f2f3d33033e9bd53c1f5' 
  AND token = 'bYEIQTtVCG8IAvho7YYLBu6Hr+P4xoPpSJk9FBLHj0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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