SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3550d7be3e420ecdba8fc03ab14c2b784c05b432cf5c06cfb89ae45bbee7b03a' 
  AND token = '//AdAkSXQ4KAUarWo3D67u2OFHsnINhszHd+Pl78Iuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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