SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1273c937d8ab9c336d614c6ec4a6468a3dd33a439dbe182a8afad69c421030a9' 
  AND token = 'yb6IiUZkNCGXlSI+DV20XU4gDtDstEM/wtE0NLsS1Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}