SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966db7f14ce26291a495e84c1e4c012b070b75bd89006aadb40b98b4d99263b4' 
  AND token = 'YEEkCF660VudXbb6jT7wvJ45oYgtE+CavlOy4hHLEvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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