SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c37d57de41d1f457e7cd86d2b7b9f9a259edc8654e87dbd8043fb3274f33bdf' 
  AND token = 'zlfk8LrTDf/3lyqPlCTBpNKZQvC7i9A0hYO6SSqX+QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}