SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '788da20b19d737fbfe8865d9e738d97df236ad4b78daa16ee9559ad9d5f60d45' 
  AND token = 'frzobsBuUGi849copB2N6FGE332n56SS5UqCsf3w8lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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