SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59af935518fea91d2f329d114f9a3bc44c80d9b226a4d28a4955c73d7290db5' 
  AND token = 'jqsJEuM6H/idLS+l8PNFxRarZ7NqQ0RpVIrfJhHCb3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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