SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3564e16359a768b2f3e82a68e878efc18e0f9e5ebf5a8cb1622c43eb85fe2cb' 
  AND token = 'KcUKBDO2ASGSKruXODwbRJaY3OD6qKj/xurw+rSg5xQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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