SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3bf3305a02beb250e0da3292f450886075128263e5e94fc04855111d95db952' 
  AND token = 'dFvoOjNZIGUcU+sMrbWoLG7QeyYkYzEibbxAEY4NT6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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