SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9203854e931c835db9cffa236bec99418f390acbf791a220d8ad19f7835d04a6' 
  AND token = '15HxPtoNHr5tN1hTcfa4Y5hxigabtjiTIbQ+AXcCijI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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