SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b31bd5cd357f96232b4279fb042e2495fee76695dcdda9abae9131559af4d9cd' 
  AND token = 'w8GqS9W8Avb4fFjbVdqTLGJKB3daKc/chPKAOoszVgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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