SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '373b56ca9b4685593addb42cec071f1a43d024af99f0aee77904a22c858284a5' 
  AND token = 'hXXKLJ0nYth4PxUqumwpcbOByLYddhkuVeVmH4e1GFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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