SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861558b7f92ca599be2b54900bfe144a9bbfade1d047d9c30fc5d5971199b344' 
  AND token = 'HE4+A5+NHzA/tOIZL7vRdQHXgctokFL4RSoSiQdBmf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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