SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ca8aa0d1e576dac2676c817f8d2c056a14bd039bff29459cb04cb746c9cdba' 
  AND token = 'IZx4EWfFGjR9DxvKIJHYCclAUYSX+ZXDEJmg2AnjPqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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