SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20eed68853fed79cde12e6bee16c9a5214b49d39d7ab6f1f7c09551259c3fda4' 
  AND token = 'FfcFdv8mpk/gbuK9MNuVUgbBpCAXTbTM8XNlcdOxpa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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