SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cd46dd56512288eb61c916be6ac08e24164d0157aee60517b7e32eeaa62d879' 
  AND token = 'kd4vVIo4p39HygFHbd3MssFEvmnwRb7qVPG8Rv5We4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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