SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89abd0096c812e6ddee3375949f038ace2d5b29dce4db2712dca1a1bb9afdf9e' 
  AND token = 'i0YPiZ+1yro+pt7xRMJbtJU5QQpTuVXlwMfuotBA1t8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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