SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a19be1629a92d48a5842ca3e91e397982faecb7b64b51132d61b00e2c1175aaf' 
  AND token = 'e/EtfHc3iyWyIKIU+IEbLcoZjPbrOiBPoDyucOnJlhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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