SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31c1141cd262b87c9819297189075884ae1df0b83e496011cb211d79aeb2d3b5' 
  AND token = 'r0e3u/OFn7DFKMMkxdSQyiEuUDwviLTrNxrWzOA0MAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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