SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec7f2f906b3ec9cc688b196f38586f920dcf8c68128c1ca9612a1266e0935f9a' 
  AND token = 'oBQLIdqHECYB4rbtQyXaQj98cHVlCdBXFOqd3xii0mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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