SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611ea576a8bf4848e4ff0190bfc77a0245769fdbd6f8a250c079ebe040d10553' 
  AND token = '7nBlyMhzDG6dR1tYa+d1yiWnw1T6DJqpbCfVk1HAbfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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