SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49168a05334777b16b94107bd6250c4a72340729c7263da519072b503de318b4' 
  AND token = 'YojBphskvK+kQWC4YnPUSOre+VYO86B31znAJpKOfQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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