SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ecadf6d72eb24d9114b65d09eba7431dd1f95272036d7b8156fbcaf14b89394' 
  AND token = 'bEqZsIMsHI7ykU7+myWL/e7jJsceulJE9wZcnOFpQ0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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