SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '164087966f25877585166728ebf2c96548d7049f723f34eb0e58371a6e9e9f35' 
  AND token = 'GQiEJEDDK3cb328C4MDFkGq1artIYgiRJ14mup8/LAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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