SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2fc2021c7245dabef5f473197475eb234881cfea1f2cb0b2a460919967fec2' 
  AND token = 'rWm0ZmESOntKVGDKLoZnv5Y90rt1T9h9rq/gAx38IEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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