SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3caf4876c063d230b813958ae4465d450a2da8cebab4fb4640a9b6ebda70ef5e' 
  AND token = 'jUZwCEmegsmkLSpGP83L7eP5eZR+YlZ1H8Ng2oXI+aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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