SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fca7708cff21af21b5dd2bf9f7d78232d977b6b3bcdcbd579b2c92d9d7457134' 
  AND token = 'JnDqZ4O9lhBQbVvl/6MudNzPN9OmK54/GzjcPHiYe9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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