SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b90c3ab396f559bc5fb4d7c163ab1bae20039daa55c8c93672d5e86b02f84d16' 
  AND token = '+ZOLLpoTfgF8VJ3NWW/v+aoz+9vAN6WLzvBLI4bVsYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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