SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '658721368abe92bf1ed297c8995725be40e699a6be80f49fff29926622f2d3af' 
  AND token = 'MGC0iEpDnjjiSmWT6elwXzaVSU1GG4Rh/Z8iByBTQ7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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