SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f88cbfb405b7e067b46747081897cbd2f59c147c373f29749ea44da52396aa9b' 
  AND token = 'sYzW79pfiUR2Rxpg6iyTTQ2HO3lNX6mG4p6OS5tZx/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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