SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7500ee95d7e0aac0a94fda57bf9274d3e2c7023d45bfac3178bc95ce87fc721' 
  AND token = 'EByXc9WRqOtfoORXaKxUASfLvVpfEdg5gtRs0EgZDPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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