SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db0f14d6f797fda31d7b33a27970ad1cd1f607ec83a968e9a204e4babc4571ce' 
  AND token = 'dy16b235GrXMzrPYBkUDQxQ5Y0XTXcpbvrePMBADULU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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