SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a71dc30094b7db7a23a046c1f5a948153dd83f695a378e41fd6cce4e2ce60d' 
  AND token = 'HaqjR7rIzWbQYcbC1X+7edVs5YUmGmrrjR/i1Znxnk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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