SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c94ad28b49994d07a1a6a38b345c73228ea6d729bdc9772466ccc99851c3c916' 
  AND token = 'J5Mn5lirHdyo2iSxElLfDdD7VfexwyKvmw6J3plph3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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