SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd80da90ff5f881e8306682481aa2c8940455fa0b9d29a7aaa1523ca086065650' 
  AND token = 'UIwb3zVyMQZS8oy10JPk3oEx3Gbt5+WMwPGaXWT/pOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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