SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b83fc7ec88f469a20fbb8ed86aafa79c066c0aa10f4f80343581f4bf45932f4' 
  AND token = '+1bE5Tjm4mY61Ac3Jh/tgpvhGloAYqA5SCVnjPo2Ktw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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