SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc78d21ebc9f679b491cb03b8b8368bb54b0017ea559200b3d4aa7df920f8a2' 
  AND token = 'LPnxgUlwewifvuBT+IY/PgZsYENbAA6wFotCRUrRWFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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