SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90fe73c500adcdf5a1f3d1fb506b0fb4bb39aad3796d854b69bb14c32210aed5' 
  AND token = 'ah7xHgbqIjcrv/biZLXSzx7eTwJQP34wyaL4/zENlAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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