SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc80d57ac6b76234bbf4d0292021fc869dc3be66e00a6f40e8bb7ee214f99bf' 
  AND token = 'StoqARhNJI9ktjiFBWdjlbOZXgUEZwGSo3jZmr5hHqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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