SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e74dcaadde9067965f7182a3825cbc8542a5b1bc216e1c8c42a8e2e45419e715' 
  AND token = 'AiWyX8Rxpv0JuFdzW+5NjIrxH8GU3mxwGw1YnPwiXfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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