SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12b223fc55368ef0f5b1a77a1d08ef81c1996eda1100aba3495282d27634d1ed' 
  AND token = 'RQEbLsBpC0LspIQlT4doTheE6E3XlhfshoIW8PCqMzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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